If the rumours are true, the Iron Garrison is in danger and their foothold in Khazad-dûm is threatened.
You have entered Khazad-dûm from the East-gate, and the situation appears worse than you feared.
Bósi and Brogur have not yet made it back to the East-gate. Solsi asked you to find them, if they still live.
Brogur is on the western side of the First Hall.
Bósi has made it to the First Hall.
Brogur fell behind during the retreat, and Bósi asked you to find his cousin.
Bósi is in the First Hall, near the East-gate of Khazad-dûm.